A major effort of Core A is to analyze human and mouse plasmas and serum for lipoproteins and their component lipids and apolipoproteins. The lipid analyses employ automated micro-method techniques to determine levels of total cholesterol, HDL* cholesterol, unesterified cholesterol, triacyglycerols, glycerol banks, and unesterified fatty acids. Human plasma LDL and VLDL concentrations including apoB, apoAI, apoAII, and Lp(a). In addition to the measurement of lipids, lipoproteins, and apolipoproteins, the Phenotypic Marker Core also determines levels of several other plasma factors related to lipid/lipoprotein metabolism and atherosclerosis, including plasma concentrations of insulin, glucose, leptin, and the enzymatic activities of lipoprotein lipase and hepatic lipase. All of the assays required to determine the phenotypes proposed in this Program Project are currently in use in our laboratory.